Archiving image and video information is a very important task in several application fields, such as television, road traffic, remote sensing, meteorology, medical imaging and so on. It remains hard, however, to identify information pertinent with respect to a given query or to efficiently browse large video files. The approach most commonly used with the databases consists in assigning keywords to each stored video and doing retrieval on the basis of these words.
Three standards have already been defined by MPEG: MPEG-1 for audio- visual sequence storage, MPEG-2 for audio-visual sequence broadcast, and MPEG-4 for object-based interactive multimedia applications. The future one, MPEG-7, will provide a solution to audiovisual information retrieval by specifying a standard set of descriptors that can be used to describe various types of multimedia information. MPEG-7 will also standardize ways to define other descriptors as well as structures (description schemes, i.e. ways for representing the information contained in a scene) for the descriptors and their relationships. Such descriptions will be associated with the contents themselves to allow fast and efficient searching for material of a user's interest (still pictures, graphics, 3D models, audio, speech, video, . . . ).